Method of carbonizing fuel.



H. L. DOHEB TY METHOD OF CARBONIZING FUEL.

- APPLICATION man JAN.29,1915. Patented Dec. 121916.

H. L. DOHERTY. METHOD OF CARBONIZING FUEL.

APPLICATION FILED JAN. 29, I915.

Patented Dec. 12, 1916.

3 SHEETS-SHEET 2.

Ll l l I PLI H. L. DOHE RTY.

METHOD or CARBONIZING FUEL.

UNITED sTArps PATENT oriuon.

HENRY L. DOHERTY, OF NEW YORK, N. Y.

' METHOD OF CARBONIZING FUEL.

Patented Dec. 12,1916.

Original application filed November 15, 1911, Serial No. 660,450. Divided and this application filed January the same into gas.

This application is a division of my application Ser. No. cacao, filed Nov. 15th,

1911, in which application I claim the broad features of the invention herein dis- .closedj The object of .my invention is to improve the manufacture of illuminating gas from fuels containin hydrogenous matter in retorts or the lilie by reducing the proportion of fuel required for heating the retorts, by taking the gas ofi of the retorts in a comparatively cool and pure condition, whereby the size of the apparatus required for the cooling and purification of the gas is diminished and thepurification facilitated, by quenching and cooling the coke in the retort itself and at the same time returning and utilizing its sensible heat in the carbonization, by makingit possible without change of apparatus to either recover the volatile tarry products of the coal separately from the main body of distillation gas or else to wholly convert the same into permanent gases and fixed residuum, as well as by the introduction of various minor features of treatment which will be described in detail below.

Briefly stated, my invention comprises the carbonization of fuel'in elongated vertical chambers or retorts which are heated at a middle zone only, the portion of each retort above the said middle zone serving as a fuel preheating and tar condensing chamber, while the portion below the middle zone serves as a cooling chamber for the car bonized fuel.

The retorts are, during operation, always maintained fully chargedfresh fuel being .charged in at the top as carbonized fuel is withdrawn from the bottom. The

gases produced by the distillation of the 29, 1915. Serial No. 5,110.

fuel in the middle zone are drawn off from the upper part of the retorts, and therefore through the mass of relatively cool fuel in the preheating chambers. The relative weights of fuel and gas will usually be such that the gas will be cooled down to at least 300 F., at which temperature substantially all of the heavy tarry matters of the gas will condense, the gas discharging comparatively cool and free from tar, but carrying water vapor and such light hydro-carbons as benzol, etc. The carbonized material is drawn down from the carbonizing zone proper into the cooling zone and there cooled by a current of gas or steam, or a combination of the two. For the cooling current it is advantageous to use a portion of the distillation gas itself after the re moval of its illuminants and ammonia,'.together with more or less water vapor. The water vapor may advantageously be generated by the sensible heat of the gas as it is drawn olf from the retorts and the latent heat of the water vapor which it carries.

By evaporating the water directly into the deluminated gas returning to the retorts the 7 carried out at a temperature below 212 F., by reason of the presence of the gas. The mixture of deluminated gas and water vapor passes up through the carbonized fuel in the cooling sections of the retorts, taking up the heat of the fuel and quenching the same, and at the same time facilitating the evolution from the carbonized fuel of the residual volatile matter which it contains. The returned gases then pass on up through the retort and join the main stream of gas which is being evolved from the fuel in the carbonizing zone proper. A portion of the evaporation may be volatile matter of the fuel is driven off from carrying it down into contact with the hot coke in the lower part of the preheating region of the retort whereby the tar is revaporized. The returned gas laden with the tar vapors may be then either drawn off at a selected point above the carbonizing zone proper or else drawn down through the hot carbonized fuel in the said. zone. In the former case the tar vapors may be again condensed, while in the latter case the tar is converted by the hot coke into permanent gases, difiicultly-condensable hydrocarbons which may be utilized in the enriching of the distillation gas and fixed residunm which deposits in the coke increasing its density and hardness.

y invention also comprises various other features which are set forth below.

In this application-I claim specifically the feature of the process, briefly describedabove, which deals withthe method of operation inwhich the 0001 returned gas is periodically introduced at the top of the re- .torts and passed down through the tarladen fuel in the preheating chambers to blow the ta rry liquid out of the. interstices of the fuel therein and carry it down into contact with the hot coke in the lower part of the preheating region of the retorts, to convert said tarry liquid into gas.

It will be seen that my process in part may be summarized in general terms as a pipe- I ess of heating and treating materials which and bringing the gas thus heated connections.

detail on an enlarged tion of a fuel conveyor and the method ofv comprises advancing material to, through and beyond a zone of high temperature,

wherein changes in such material are accom-.

plished, cooling the hot material beyond the said zone by a current of cooling gas,

into heattransferring relationship to cool material advancing toward said zone.

In the drawings I have shown an apparatus embodying my invention and adapted to use in the carrying out of my process.

Figure 1 is a vertical cross-section through oneof the beds of the bench with its cooperating gas producer on the line AB of Fig. 3 and line AB of Fig. 4t. Fig. 2 is a rear elevation of a portion of the bench showing the lower mouthpieces and the arrangement of the gas connections to the same. Fig. 3 is a partial plan of the apparatus. Fig, at is a horizontal cross-section through one of the beds and its cotiperating furnace at the line .A-B of Fig. 1. Fig. 5 is a vertical cross-section through a recuperator on the line-EF of Fig. 11. Fig. 6 ,is a horizontal cross-section of the same bed on the line C-D of Fig. 1. Fig. 7 is a detail view on an enlarged scale showing a side elevation of one ofthe gas off-take Fig. 8 is an elevation of the screening device and fuelv bin. Fig. 9 isa scale showing a por- 1. Fig. 12 is a vertical cross-section through the water evaporator. -Fig. 13 is a detail showing a vertical section through one of the water distributers of theevaporator.

In the several figures, A A? etc., are the retorts, 1, 1, etcuthe cerbonizing chambers of the retorts- 2 2,2; are the preheating chambers of the same '5, 3, 3, etc, the fuel cooling chambers of the same.

it and 5 are, respectively, the rear and front walls efthe bench shown in Fig. 1.

6, 6, 6, er, are the gas-producing furnaces of the bench. I

.7, 7 etc'., the fuel hoppers of the furnaces 6. 8, 8, etc., the discharging doors of the 13, which elevates the mixture to the screening device 14, from which the screened fuel passes to the bin 15.

16 is a bin for storing the raw coal used in the producer. 17 is a bin for the coal used in the retorts. 18 is a coal conveyer which is so con structed that it transports in turn both the fuel charge for the furnaces and that for the retorts.

72, 72, etc., are small lateral conveyers which receive the retort fuel from the conveyer l8 and transports it to the mouths of the retorts.

19 is one of the air ecuperators of a bed,

while 20 is the heat-interchanger of the same.

21 is a deluminator or scrubber in which the portion ,ofthe gas returned to the retorts is scrubbed with what is technically known as '2 V wash oil to absorb the illuminants from the gas.

10. is an ammonia scrubber through which the gas passes after leaving the delumina-- tor '21. r

22 is the hydraulic main which receives the normal gas from the dry mains 23. There is, as shown, one dry main for each row of retorts.

24, 24, etc., are the valves on the dry mains. 25 is an auxiliary hydraulic main which receives the gas'drawn off of the retorts during reversal through the dry mains 26 or 27 according to whether the tarry matters are drawn off in the volatilized or permanently gasified condition. I 1

"'11'Qjisthe water evaporatonf 1 The methodof operating my apparatus is ieo to the upcast flue 35.

as follows: In starting operations fuel beds are built up in the furnaces by any preferred method. By one method coarse screened cinder is first charged into the furnace chambers until the coolers 11 have been filled. Fires are then kindled in the furnaces, air being supplied by the blowers 28. To permit this, the pipes 29 connecting the inlets of the respective blowers with the upper part of the preheaters of the respective furnaces are each provided with a branch, 30, in communication with the atmosphere. By means of valves 31 and 32 the blower is put in communication with the atmosphere while the connection to the top of the preheating chamber is cut off. Air in excess is thus forced up through the cinder in the coolers and supports the combustion of the ignited fuel thereabove. The products of combustion pass off from the furnace through the regular gas off-take fiues 33'to the equalizing flue 34 of the heat-interchanger 20, thence Passing up through 35 the gases go through the fan 36 and are thence impelled down through the down-cast flue 37 which is separated from 35 only by the comparatively thin sheet-metal diaphragm 97. This, as shown, is built into the front wall of the producer. The fiues 35 and 37 are formed by off-setting a suflicient number of bricks in corresponding vertical rows in the inner portion, 98, of the front wall of the producer. The metal sheet 97 is then set in place resting against the projecting bricks of 98, and extending a suflicient distance all around beyond the flue space 35 to prevent a flow of gas around its edges into flue 37. The outer portion, 99, of the front wall is then built at the same distance from the sheet 97 as is the face of 98. Bricks, corresponding in position to the projecting bricks of 98, are off-set from 99 against the sheet 97. Around the outer margin of 97 the wall 99 is built directly against- .the sheet 97, as is the wall 98.. In the upper part of 97 an aperture is out just the size of the gas inlet to 36 and corresponding to it in position when 36 is in place. There are thus formed two vertical flues, 35 and 37, which are in communication with each other only through the fan 36. Since'the initial temperature of the gas entering 37 in normal operation, will usually not be over 1500 F., and the character of the furnace gas will be reducing rather than oxidizing, it is evident that either wrought iron, soft steel or cast iron may be used for constructing 97. While, it is true, that during direct combustion the gases are oxidizing in character to sheet iron, their influence is not exerted 1 for a sufficient length of time to be materially injurious to 97. Should the sheet 97 temporarily permitting the gases generated therein to escap J to the atmosphere through 30, shutting off communication between the furnace and 35 by closing the fiue 33 by the tile dampers 100, operated through the openings 101, t aring down the portion of the wall 99 constituting the outer wall of flue 37,

inserting ,a new diaphragm and rebuilding the walL/ During the period of banking the flues t l, and 41' should be closed by tiles 102 (accessible through openings 103) to prevent the indraft of cold air to the retort setting.

It is obvious that at the start of operations the gases will be subjected to a gradual co0ling as they pass through the fiues since the setting is cold and contains more or low moisture. The gases therefore reach the fan at a lower temperature than that at which they enter the lower end of flue 35. charging from the periphery of the however, they are impelled down thro'gh the outer flue 37 and thus subjecte to a reheating by thehotter gases Pass' g in the reverse direction through the flue It is plain that a heat differential having once beenestablished between the two streams of gas, will thereafter be maintained indefinitely as long as no extraneous heating or cooling action is introduced. The amount of this heat differential will, in the absence of any extraneous. influence, depend entirely upon the superficial area and heat conducting power of the walls of the flues and upon the velocity of the draft. In any given case, however, within certain limits, should the; size of the fiues 35 and 37 be too small, the

normal differential may be increased by admitting an appropriate cold gas into the inner flue 35, through the pipe 38, which is, in the construction shown, connected with the stack 39 of the reouperator 19, thus permitting the introduction of relatively cool combustion gases into the gas approaching the fan. The addition of the cold gas, of

course, lowers the temperature of the gas device, therefore, I am able to move hot gases with ordinary fan blowers without any sac; rifice of the heat of the gas. This inven-' tion, however, I do not specifically claim herein, it forming part of another application.

From the flue 37 the combustion gases pass through the ,collectin gflue 40 to the side flues 41 and'4 1.. 'From 41 and 41 the gases flow into the transverse flue 105 and thence distribute themselves to the three combustion fines d3, 43, 43 through the-ports Flowing back through the fines 43 in contact with the walls of the retorts and setting the gases pass around the end of the horizontal baffles 106 in the fines 43 and thence forward through the fines 43' to thefront of the retort'oven, where they leave the oven through the gas off-takes 44,

which communicate with the cross-flue 45. From the combustion gases pass through the fines 112 and 112 -t0, respectively, the combustion gas Hues 46 and 4:6 of the respcctive recuperators 19 111N11 through these, and finally discharging through the stack 39 to the atmosphere.

4E8 of the recuperators 19 are; gradually opened, permitting air to flow through the air flues 49 of the recuperators, thence through the connections 113 and 113' and the fines 50 and 50 to either one or both of the cross-fines 109 and 109 andthe respective sets of nostrils 51 and 51 into either one or both of the sets of combustion fiues 43 and 43. By means of the dampers 110 and 110 on, respectivelg, the connections 50 and 50, which COIIHBCMQDS establish communication between the fines 50 and 5.0 and the cross-flue 109, the distribution of the air between the Hues 109 and 109 may be regulated at will. Operating rods 114 and 114;, connected withllO and 110 respectively, permit of the manipulation of the dampers. Since the walls of these Hues 43 have been previously raised to the temperature of ignition of the combustible constituents of the furnace gas by the direct firing, the combustible constituents of the gas issuing from the ports 42 are burned by the air entering from 51. When the fuel bed has been built up above the primary current inlet 52, the remaining fuel required to fill the preheating chamber may be rapidly charged. The blowers 28 are now connected with the upper part of chamber 9 by shutting valves 32 and opening valves 31. A portion of the gases generatedin the furnace 6 are now drawn by the blower 28 of each bed up through the fuel occupying the preheating chamber 9 of the furnace 6, whereby the said portion of the gases 1s cooled and the said fuel preheated. The por-' tion of the fuel the lower part of 9, when the charge contains bituminous coal, is carbonined, the distilled gases passing up with the stream of gases diverted from 10.

In passing through the fuel in the lower part of 9 any CO or H Othat may be in the diuerted current is subjected in greater or less degree to reaction with the carbon of the incandescent fuel, thereby forming combustible gas. The cooled gas mixture is drawn off from 9 through the pipe 29 and thence forced through the pipe 29 into the. lower part of cooler 11. Passing up through the fuel mass in 11, which has been subjected to partial combustion in the gas making zone 10, and therefore contains more or less ash, the gases introduced into 11 take up thesensible heat of the fuel mass, at the same time cooling the latter. By properly proportioning the volume of the gas introduced into 11 to the rate-at which the solid material is withdrawn from 11 through the discharging door 8 the fuel and ash mixture may be thoroughly cooled before it has reached the dischargingdoor 8. The heated gas passes vupward through the fuel in the gas-generating chamber 10 find joins the main draft current of the furnace. At the same time that the pipe 29 is connected with the preheater 9, the speed of the fan 36 is increased and the various dampers set to provide the furnace with its normal primary draft. This, under normal working conditions, is composed of either partially burned gases drawn off from the fines 4:3, gases of complete combustion drawn off from the fines 43 or of any mixture of the two required to regulate the working of the furnace. i,

In normal working, the furnace gas is not burned completely in the lower combustion fiues 43, but the air admitted to the fines 43 from the nostrils 51 is restricted to that required to develop the quantity of heat which is demanded to maintain the proper temperature in the sections of the retorts in flues 43 and'43'. The b alance of the secondary air that is required'to secure complete combustion ofthe furnace gas is admitted, by opening the air dampers and 110 by means of the operating rods 11 1 and 114, respectively. A portion of the heated secondary air now flows through the short connections 113 and 113 to the upper cross-flue 109 thence through the air nostrils 51 into, the partially burned gas which is flowing through the fines 43 to the rear of the bench. Enough air is always introduced athrough the nostrils 51' to insure the complete combustion of any unburned constituents remaining in the gases by the time they have reached the flues 43". Since the inductive efiect exbustion fines of the retort oven, by the stacks 39 and the fans 36, is greater in the flues 43- than' in the lowest combustion fiues 43 the air will tend to ,flow from 50 andi50 through thefconnecting fines and the nostrils 51 in preference to the nostrils 51. It is therefore only necessary to regu- 'latethe draft through the connections 113 time it reac and 113 by means of dampers 110 and 110 and the main air dampers l8 and 48 to secure complete control of the distribution of the air between 51 and 51. By means of the dampers 110, 110 this distribution of the air is so regulated as to secure as uniform a temperature as possible throughout the combustion flues 43, 43, 43 and t3".

The primary draft for the furnace is, in part, drawn oil from the dues 43, by diverting a portion of the partially burned gas flowing through 43 through the nostrils 55 into the cross-flue 85 and thence through the fiues 84 and 84: to the primary inlet flue 56 which discharges into the space 52 above the surface of the fuel in the furnace. Dampers 107 and 107 on 84; and 84, respectively, serve to regulate the volume of the partially burned gas withdrawn from the fines 43. The balance of the primary draft current is made up of completely burned gases withdrawn from the main combustion gas flue 45 through the flue 4:7 in volume regulated by the damper 4:7. The two portions of the primary current mingle in the inlet fiue 56 and are drawn from 56 under the inductive action of the fan 36 into the space 52 in the chamber 10,:abve the surface of the fuel, thence the larger portion passes down and across the column of fuel in 10, emerging into the space 57 above the free surface of the fuel.

and pass through the gas off-takes 33 to the heat-interchanger 20, as already explained.

Both the portion of the primary current drawn off from 43 and the portion drawn off from the flue are at a comparatively high temperaturefrom 2200 to 2500 F. While the initial temperature of the primary current is somewhat reduced by the es the furnace, still it should enter the fuel bed in the latter at a temperature above 2000 E, and usually at about 2200 F. In passing throu h the fuel bed in 10, more or less of the car on dioxid of the primary draft and the water vapor carried by it react with the carbog of the fuel to form carbon mo'noxid and hydrogen according to the reactions g Both of these reactions absorb a large amount of heat, which is supplied by the sensible heat carried by the primary curand - rent at its entrance into the fuel bed, and

- from the air and fuel,

sometimes by a portion of the sensible heat 'of the fuel itself. Since, by my method of 'nace is unimportant. We only need, therefore, to consider the action of the carbon dioxid. This reacts energetically with the carbon of the fuel at temperatures approximating 1800 F. and above, but less rapidly as the temperature falls. More or less reaction takes place even down to 1300". It is evident, therefore, that by regulating the quantity of ()0 carried into the furnace and the quantity of heat accompanying the CO by regulating the draw of gases from 43' and "15, respectively, I am able to maintain the fuel bed in the chamber 10 of furnace 6 at any temperature desired within the working range.

In order to secure complete combustion of the gases in the combustion flues, it is necessary to introduce a slight excess of air into the flues from the nostrils 51. The portion of the primary draft drawn off from 45, therefore, will usually contain a small proportion of free oxygen. This, of course, burns a corresponding quantity of fuel in 10 to form CO, with the generation of heat which helps to support the reduction of the accompanying CO Under normal working conditions, however, this excess of air is kept as low as possible. This portion of the draft current, therefore, has a strong net endothermic orglgeat-absorbing effect. The portion of the *p'riifi'ary draft withdrawn from 43, on the other hand, carries under normal conditions more than enough sensible heat to dissociate its own CO, by reaction a and has thus a net exothermic or heating effect on the fuel bed. By varying the actual volume of the primary current and properly proportioning the two separate streams of gas making up the same I am able to control the temperature of the fuel bed in 10 and also the quantity of combustible gas generated. The volume of the gases drawn through thefuel bed is, of course, controlled by the speed of the fan 36 and the various dampers on the several conduits. This also serves to control the proportion of the CO of the primary draftwhich is dissociated, I

since by varying the volume of the primary draft I vary the speed at which the gases pass through the fuel bed and therefore the time they are in contact with the hot fuel.

I Contraryto the practice in producer firing, I do notaim to dissociate the maximum possible proportion of the CO of the draft current in the furnace. On the contrary, in normal working the gases are circulated through the fuel at such a velocity that the dissociation is usually less than 50% of the total CO that passes through the fuel. I am thus able to easily maintain the temperature of the fuel at a point that insures its maintenance in an active as-making condition by th sensible heat lntroduced by the large volume of gases passing through it. My combustion process may therefore be comzone'of'the furnace. -They are gradually prehensively described as the maintenance of a continuous circulation of gases-from the furnace to the retort oven and back again to the furriace-the return circulation to the furnace consisting of a balanced stream of completely and incompletely burned gases. A volume of completely burned gases corresponding to the air introduced into the combustion fines of the retort oven is continuously rejected from the circulation and sent through the air recuperator. By thus circu- (atin a large, volume of gases at high veloc- .ty t n-ough the combustion fiues and the fuel bed of the furnace, as well as by distributing the combustion through the fiues, I am able to secure the proper heating of the retorts without the necessity of maintaining an excessively high temperature in. the come bustion fines, since, as is well known, the velocity of heat transmission through the re torts varies with the velocity of the heating gases along the walls. No increased loss of heat in the rejected gases is occasioned, since the volume rejected from the circulation corresponds to the volume-of air used and the two currents in the recuperators are thus about balanced in their thermal capacities.

The abo e described method of combustion Lres 've the right to claim in a sepa ratefapplication.

he minor subdivision of the furnace gases passes up through the furnaceishaft in contact with the fresh fuel in chamber 10.

It thus cooled While the fuel is at the 'same.

time heated-that in the lower part of 9 being carbonized. In passing through the short column of carbonizing fuel more or less-of the reactive constituents of the minor T subdivision of the primary current sufl'e'r dissociation.

therefore contains-some CO as well as the volatile matters distilled from the coal.,.;

These lat r are condensed by thecold fuel in the up ger part"of 9--, being absorbed by the coke forminga l-arge 'propo'rtion of the charge'and again carriediidown into. the hot evolved from the pores of the coke in contact with the hot coke and are more'or less broken down into permanently gaseous com' pounds. may be again volatilized to be again conjdensed and carried down. This operation being repeated continuously until all the volatile matter is finally converted into noncondsenablegases. The mixed gases are drawn ts from 9 through the pipe 29 and forced by blower 28 into thev bottom of the furnace; Being comparatively cold, they take up the heat-ofthe fuel and ash in 11,

quenchingthe fuel and cooling, the mass. I

aim to :cool in 9 andgintroduc'e into 11 just the volume'of gas-required to" quench and cool the fuel. "Since at'zleast aboutone-half of the charge consists. of raw coal it is ob- The gas passing through 10 -po'rtions ofcoked'" andraw coal are dis charged onto therconveyer 18 and transport- A portion of this volatile matter vious that the weight of material withdrawn. from 11 will be much less than that charged into 9, for, besides the fuel burned, there is a diminution in weight due to the volatile matter and moisture driven oil from the coal. The heat capacity required in the gas used for cooling the material in 11 will therefore always be less than that of the fuel charged in the same period of time. For this reason, suliicient cool gas to quench the material withdrawn from 6 will always be available.

The mixture of unconsumed fuel and ash withdrawn from the furnace at 8 falls into the bin 12 mounted on the truck 58. From 12 the material is gradually discharged onto the conveyer 13 and elevated to the screening apparatus-14. The mixture of fuel and ash is dumped into the hopper 59, and' passes from this onto the grizzly or per 'girated screen 60. is constructed with'h arrow apertures or slots of a Width of not more than say inch. Air under a slight pressure entersthe blast box 61 beneath the grizzly from the pipe 62. The 'air passing at high velocity through the grizzly, and the material passing over it, takes up the-fine ash and carries it over into the ash pipe 63. The

the gate 64:.- The two ash streams are conveyed away through 63 to a dump or directly to carsfJhe screened coke discharges from 60 through the chute 65 into the bin 15. The

h in; 16 receives the raw coal which forms fiartgaof thewharge for the furnaces and .j 'vvh-i'ch 1s deliveredinto 16 by the elevator 66. jFr-om thebins'fi and 16 the properfprd ed to the furnaces. The conveyor 18 as shown is usually an ordinary belt conveyervided with discharge openings 69'which are ordinarily closed by gates. These dischargeopenings are provided externally with short chutes; 7 0, so located asto discharge directly into the fuel hoppers 7 of the producers. When it isdesired to fill the fuel hopper of any particular producer, the gate 69 above that hopper is opened, the dam 71 inserted in the conveyer chute above the belt and .1

the conveyer started. When the fuel arrives at 69 the dam 71 diverts it into the chute 7 0 from which it falls into the fuel hopper 7 When charging the retorts the conveyer 18 receives the gas-coal for the retorts from the blIl 17 and discharges it onto the lateral conveyer 72 through the gates 73 in the wall 68 139 of the conveyor chute.

. of the fuel mass, on the one hand, and the The dam 71 is inserted into the slots 74 so as to divert the coal through 73 onto one of the conveyors 72. By setting the dams 71 at successively greater depths, several or all ofttthe lateral conveyors may be used at the same time, as

in this case the successive dams, up to the last, simply scrape each a shallow yer of coal from the conveyor 18. From 72 the coal is discharged into the open mouth-pieces of the retorts through arrangements similar to those used in the case of 18.

In starting operations, I prefer to chargethe retorts A up to the chambers 2 with screened coke, the upper portions, 2, only being charged with coal. When the charge in the chambers 1 has been thoroughly heated up tothe proper carbonizing temper ature the system is in roper conditionfor establishing the norinzfi circulatipn of the gas currents. Part of the cold coke. or carbonized fuel in 3 is drawn, a corresponding volume of coal or other fuel descending from 2 into 1', and of hot carbonized fuel from 1 into 3, and the preheating chamber '2 is again charged with fresh fuel.

The height of the preheating chamber 2 will depend directly upon the rate of descent velocity of the heat-carrying gases, on the other. It is advantageous tohave the pre-' heating chamber of a height of from 5 to 10 feet, although this dimension may be varied more orless according to circumstances. The'same statement holds true in the case pf the coolingchambcrs 3, although the capacity of the coolers should generally be greater than that of the preheating chambers 2.

The gas evolved from the fuel during the carbonizing operation in the retorts is drawn. o'fi from the retorts .through the. Venturi throats 82 and connections 53 from the vmouthpieces 5. 1 to the dry mains 23 and passes thence through the conduit 22 (which may be a hydraulic main as shown) and the conduit 115 to the evaporator 116. This latter is simply a tubular vessel with apparatus for continuously distributing a thin film of water to each of the tubes 117. -In theapparatusshown in the drawings this is accomplished by a short sheet-metal nipple 118,

slightly belled and notched at its lower extremity so as to be held in the tube by the spring of the bell-shaped portion and at the same time permit of the discharge of the water through the notched periphery of the belled portion in a multitude of small streams which quickly converge to form a film on the inner surface of the tubes. The

nipples 118, as shown, project above the upper tube sheet 119 of the evaporator 116. Water is supplied above the upper tube sheet at'such a rate that there is maintained a small head of water upon the annular discharge openings 120 between the walls of the tube and the nipples. The water should be supplied only at that rate at which it will discharge through the passages 120 so that it will not flow over the tops of the nipples. The gas from the conduit 115 enters the lower part of the intertubular space 121 ofthe evaporator and ascends through the same in contact with the tubes. The heat of the gas is thus transmitted through the walls of the tubes toevaporate the water flowing down the inner walls of the tubes. The temperature of the gas in flowing through 116 is reduced to such an extent that the water vapor and easily condensable hydrocarbon vapors such as benzol which it carries will be condensed and drawn off through the sealed discharge pipe 122. The

hydrocarbons may then be separated from the water of the condensed liquid in the customary way by fractional distillation. The

cooled gas discharges from 116 through the conduit 123 and flows to the exhauster 75. After passing the gas divides into two streamsone stream passing to ordinary scrubbers and purifiers, while the other stream flows to the cleluminat0r 21 through the connection 124:. In this it is scrubbed with a liquid commonly known as Wash-oil in the art which willabsorb illuminants such as benzol, ethane, ethylene, etc. From 21 this stream of the ga s passes through the ammonia scrubber 10.4, in which the ammonia is scrubbed out, and then flows backthrough the conduit 7f5'to the space'125 of evaporator 116 above ,the upper tube sheet 119. From 125 the gas flows through the.

-I ma either restrict theleva orationb limy .m P y iting the quantity ofgwater to that which I desire to evaporate or else by so increasing the quantity of water that its capacityfor sensible heat below the evaporating temperatime will be increased to the point which will leave available for evaporation only the quantity'of heat corresponding to. the latent heat of the quantity of water vapor which it is desired to form. If preferred, I may bypass the deluminated gas around the evaporator 116 through the'by-pass 127 so that the cooling of the coke may be performed.

entirely by the deluminated gas.

The current of deluminated with or without the admixture of water vapor, flows back through the pipe 76"to the gas, either nietea, SI thelatter for giving an approximate measurement of the volume of gas passmg to the retorts. By this arrangement, it

- is possible to secure avery uniform dlStIlb11 tion of the returned gas mixture among the several retorts irrespective of normal inequalities in the permeability of their respectire charges to the blast. Similarly, by means of the Venturi meters 82 and valves 83 on the off-take connections 53 at the top of the retorts I am able to secure an approximately uniform draw of gas from the retorts irrespective of normal differences in the re sistance to the blast offered by the charges in the several retorts. I therefore aim to control the draw from the retorts by carrying the hydraulic main 22 under a sufficiently high vacuum to overcome the resistance to the draft offered by the most closely packed retort and regulate the draw on the other re torts by the flow of gas deduced from the indications of the gage 82.

The cold deluminated gas or deluminated gas and water vapor entering the bottoms of the retort-s ascends through the material occupying the coolers, quenching and cooling this material and is itself heated. In normal working, the material occupying the coolers will, of course, be the coke residue from the coal carbonized in theupper zones of the retorts. The volume of cold deluminated gas returned to the retorts should be such that the descending stream of coke and the ascending stream of gas will be ap proximately balanced in their respective thermal capacities. With this condition es tablished, the coke will discharge from the retorts at nearly the temperature of the cold gas, while the gas will, in turn, enter the carbonizing region of the retorts at approximately the temperature of the hot coke discharging from the same, or, in other words, at about the temperature of carbonization. The returned gas in the carbonizing zone mingles with the gases and vapors evolved from the coal and the mixture and passes upward into the preheaters at approximately the temperature of the par tially coked coal in the upper part of the carbonizingaone. Since the maximum temperature to which the coal is;- exposed in the carbonizing zone is somewhat above 2000f F., the temperature in the upper part of the zone will usually be close to 1O0 F. The upwardly flowing gas at approximately this latter temperature will therefore extend the carbonizing action into the preheating heaters.

chambers at the expense of its sensible heat, since carbonization proceeds with considerable freedom even at a temperature as low as 750 F. The bulk of the easily con-- densable volatile matter will therefore be driven off of the coal in the lower part of the preheating region since I have as the heat carrier to the fuel in the preheater not only the normal make of gas but the volume returned to the retorts also. This action of the returned gas in reinforcing the action of the distillation gases as carriers of heat to the fresh fuel is an important function of the gas introduced into the coolers of the retorts.

The condensable vapors evolved in the carbonization will be taken up by the as cending stream of gas and therefore pass in contact with the cold fuel occupying the upper portion of the preheaters. The tarry matter, evolved in the distillation will therefore be deposited upon the coal occopying the upper. part of the preheaters. The heat capacity of the combined gaseous streani is inally greater than that of the'coal charged, since in order to cool the coke, the gas stream.mtroduced at the bottom should-itself have a heat carrying capacity of at least per cent. of that of the coal. This is because in poor gas coals the colt e see'ured will usually run as high as 70 per cent. of the original coal distilled. Since ere is not much difference between the spec'fic heats of the coke and coal, and, moreover, the temperature from which it is necessary to cool the coke is higher than the temperature to which the coal is usually heated in the preheating chamber, it is ob vious that in this case at least 70 per cent. of the practical heat absorbing power of the fresh coal will be required to cool the hot gases from the cooling chambers. When we add to this the heat of the distillation gases the combined gaseous streams will nearly always have a heat-carrying capacity in excess of that of the fresh coal. result of this is that the gases withdrawn at the top of the preheating chambers 2 will usually be at a temperature above 212 F. They will therefore carry out of the retorts practie lly-the whole of the water vapor and the benzol and allied compounds. On the other hand, the temperature of the gases drawn oil will usually not be much over 300 F. and therefore nearly all of theordinary tar-forming constituents of the gas will be condensed on the coal in the pre- The preheaters therefore fulfil: to a large cxtentth unction of condensers and the gas. mil usually be passed directly to the purifyi'g system without -further cooling.

It is manifest that there will be a gradual accumulation of tar in the fuel in the preheater, since all of the condensed liquid The from the point of condensation will encoun-.

ter a region having a temperature sufficiently high tov revapo-rize it, when it will be again returned to the region of condensation. Unless special precautions are taken to handle the deposited tar, therefore it will interfere seriously with the operation of the retorts by clogging the draft.

To dispose of the tar l adopt the following method of operation: When the deposit has accumulated to an objectional extent in any row of retorts,'the valve 24 connecting the dry main 23 of this row with its hydraulic main 22 is closed, the valves 86 or 87 and 88 opened and the valve 89 on the deluminate'd gas main 78 serving that particular set of retorts, closed. Deluminated gas or deluminated gas and water vapor, as the case may be, under the pressure of the discharge side of exhauster 75 now flows from 76' through the pipe 90 and deluminated gas main 91 to the dry main 23 of this particular row of retorts and-thence through the connections 53 and 82 into the mouthpieces. 54 of the retorts, blowing the fuel column in the upper part of the preheaters free of tar, which is carried down-into contact with the moderately hot partially coked coal in the lower part of 2, whereby it is again converted, giving vapors and gases. If thevalve 87 on the dry main 26 has been" opened the gas, mixed with some of the' vapors from the tar passes out from the retort through the connections 93 from the upper part of the carbonizing chambers l to the dry main 26, thence to the hydrau-- he main 25, from which it is drawn by the exhauster 94, and from this to some form of condensing apparatus, 200. If instead of opening 87 the valve 88 has been opened the gas bearing the revaporized tar is carried down through the highly heated coke, which in normal running fills the carbonizing chamber 1, whereby the tarry vapors are cracked down into permanently gaseous hydrocarbons, carbon and hydrogen. The resulting gaseous mixture passes, in this case, through the connections 95 to the appropriate dry main27 and thence to the hydraulic main 25, following from this the same course as the other stream of gas, just described.

Another important function of the re versal of the gas current is the prevention of an undue ascension of the hotter region in the preheaters 2 of the retorts. The returned gas being comparatively cold during its reversed flow cools down the coke in the preheaters 2 and thus tends to drive down the isotherms of the retorts. By regulating the volume of gas returned during the reversals, therefore, I am able to control and regulate the temperature gradient in the preheating chambers 2 to any desired extent.

With average coal and Lnormal working conditions a reversal of 'he direction of gas flow for about one-fifth of the carbonizing period will usually suflice to keep the fuel clear for the free passage'of gas. I prefer to reverse for about one minute out of every five or six. It is, of course, obvious that both the duration of and interval between reversals will vary with the quality of the coal used, the temperatures carried in the retorts, the weight of coal carbonized in unit time, and other minor conditions. It is obvious that by drawing off the gas from the retorts during reversals at selected levels I can secure a fractionating of the tar.

The coke discharged from the chambers 3, 8,, etc., being at practicall atmospheric temperature, ofi'ers no obstac es to conveyance. Since I prefer to use the system of operation in which frequent draws of coke of small quantities each are made, I may 13,-when that is not being used to convey the furnace coke and ash, and .so carry it to pockets or heaps.

In the operation of my apparatus, whilethis is not obligatory, Iprefer to use the system of frequent small chargesand draws,

thus approaching to co'tinuous operationl When preferred, however, the charging and, drawing may be performed at longer 1nter- 'yals and on correspondingly larger quantities of material. No Iargerquantity of coke should ever be drawn, however, than that corresponding to the capacity of the carbonizing chamber.

Instead of working intermittently as de scribed, the operation of the retorts may be made absolutely continuous. Indeed, the fact that I remove the oo ke from the coolers in a cold state and that the fresh fuel is charged into a comparatively cold chamber makes my invention better adapted. to continuous working than any other system of carbonization of which I have knowledge. To adapt my apparatus for continuous working it is only necessary to use mouthpieces provided with a suitable apparatus, not shown iii order to obviate complexity of illustratiom-which will continuously withdraw the coke at the bottom and continuously charge raw fuel at the top.

An important feature of my invention is that instead of redistilling the tar formed in the original distillation of the coal in separate vessels I can, in effect, redistil it in the retort itself. The constituents of the tar which go to form pitch may be broken up in contact with the hot coke, depositing the carbon thereby liberated in the pores of lililluo to heat /the' same I am in effect directly the coke, after an operation similar to the one occurring in bee-hive ovens, whereby the hardness and density of the .coke is greatly increased.

The principal factor of my invention in the production of a dense coke, however, is the height of the charge column. Owing to the relatively high column of fuel resting on the coal undergoing carbonization, as compared with the height of the column in ordinary vertical retorts, the coal in the carbonizing zone is subjected to compara tively high pressure. This prevents the assumption by the coke of the light scori aceous structure common in ordinary gashouse coke. By the combination of the two factors mentioned I am able to produce a coke comparable ifi hardness and density to that produced in bee-hive ovens and admirably adapted to metallurgical use.

An additional improvement in my method of carbonization that improves the quality of the coke in reference to size is the method of heating the retorts from two opposite sides only. To adapt the apparatus for carrying out this feature of my process 1t.

is best to construct the retorts with one horizontal dimension much. longer 7 than the other, the retortsbeing set in the oven with the wider faces of the-walls parallel to the combustion flue/s. By this arrangement the coking proceeds simultaneously from the sides toward. the middle, since the heating of the end walls of the retorts is s ower owing to the fact that what heat they receive must be by conduction through the thick brickfillings between the retorts. The

lines offracture produced by the shrinkage of the coke during its setting, if that term may properly be used, therefore run across the fuel column from one heating face to the other. When the retorts are heated approximately eqifally on all four sides, on the a contrary, there are lines of fracture running between each two faces. These two sets of fractures necessarily intersect and thus divide the coke into fragments which usually show more or less uniformity in their cross dimensions. In this embodiment f of my method, on the contrary, the colge tends to form into large roughly prismatic pieces having a long dimension equallto faces of the retorts.

half of the distance between the heating This quality of the coke is very advantageous from a :commercial standpoint. V Q

It should be noted'tha-t by taking up the heat of the coke in the gas introduced at the bottom of the cooler and then passing the heated gas inlcontact with the cold fuel transferring the heat, of the coke to the raw affect the heat carried by the former. It

per part of th carbonizmg zone is some what lower than the temperature in the lower. part thereof owing to the greater amount of distillation that is taking place there. The heat abstracted from this stream of gas, however, is applied to the heating of the fuel. from the processapoint of view whether the heat transferin question actually takes place in the preheating chamber or the carbonizing chamber. The practical result of the operation is that the coke is not only quenched but that its heat, in excess of the initial temperature of the coolin gas, is wholly transferred, either direct y or indirectly through the fuelto be carbonized to the carbonizing region "of the retorts.

Another important feature of my invention is the maintenance of the fuel column in a condition that will permit of the free and ready penetration of the gas current as a It therefore does not matter result of the periodical reversal of fiow de scribed. The freepassage of the gas is liable t0 be obstructed in two ways. First, the deposited tar in the column of raw fuel tends to fill up the interstices of the charge, re-v ducing the area free for the passage of the gases; second, that part of-Ithe charge.

column which is in the immediate stage of carbonization tends to become pasty, the fragments exhibiting a tendency to agglomerate to form a diaphragm across the charge column not easily penetrated by-the blast.

This diaphragm in a vertical retort takes the shape of an inverted cone, thus tending to force the gases evolved; below it to the hot walls of the retort. This results in the cracking down of a serious proportion of the heavy hydrocarbons of this gas current, with a resulting diminution of the illuminating power of the gas and. a deposition of a shell of carbon around the inner walls of the retort. Now, during the normal How of gas the pressure inducing flow is simply that cortive pressure of the exhauster 7 5. Besides,

the reversed current is flowing into the-interior of the conical diaphragm which acts to throw the draft to the axis of the retort.

The resultIof these two influences is that the reversed current tends to force its way through the interior of the charge column, perforating the pasty diaphragm in a sulficient number of places to permit of its ready passage. Besides, the reversed current now having the direction of the natural gravity flow of the tarry liquid readily blows this out of the interstices of the fuel column in the preheating chamber and bears it down into the hotter regions of the retort where it is vaporized again. When the normal flow of gas has been restored, therefore, the fuel column is in a condition to permit of the free upward flow of the gas through its interior, until the above-described obstructions have again formed, when the current is again reversed.

It is to be understood that my invention is applicable to the carbonization of any carbonaceous material containing bituminous matter, and is not limited to use with gas or coking coals,

The method of conducting the combustion of the fuel in the furnace and of heating the retorts I do not claim herein'but claim specifically in another application.

I claim:

1. In the operation of a-continuous vertical distilling apparatus for making gas and coke, the process which comprises normally removing gas from the head of the coal column until tarry and pitchy matters accumulate in such column to an undesired'extent and then forcing gas backward down through said column until the desired amount of tarry and pitchy matter has been transferred downward into the coking zone. H 2. The method of carbonizing fuel and making gas in a comparatively long conduit having an intermediate localized externallyheated carbonizing sectibn which comprises, charging the raw fuel into one end portion of said conduit, heating said fuel and dis-' tilling the volatile matter from said fuel in said intermediate carbonizing section, pass ing the products of such distillation in contact with the raw fuel occupying the said end portion of said conduit, to condense tarforming constituents of said distillation products on said raw fuel, 'redistilling the so condensed tar by periodically reversing the direction of flow of the gaseous products of the distillation to carry back the said tar into the said intermediate section of said conduit, to vaporize the said tar, and withdrawing the so-revaporized tar from said chamber.

3. The method of carbonizing fuel and making gas in an elongated conduit having an intermediate localized carbonizing section which comprises, charging the raw fuel into one end section of said conduit, heating fuel and distilling the volatile matter from fuel in said intermediate section of said conduit, passing the gases and vapors from said intermediate sectlon in contact with raw fuel occupying the said end section of said conduit, to condense on the said raw fuel tar-forming constituents of the products of the distillation, periodically reversing the direction of flow of the gas current passing through said raw fuel, to carry back the/cor densed tar in contact with thehot fuel in a intermediate section of said conduit and i re-vaporize the said tar, withdrawing the ri vaporized tar from said conduit and tran ferring the heat from the carbonized residi (fif said distilling operation :tothe said ra uel. V

i. The method of carboniz'ing fuel an making. gas in a cl sed conduit having-con paratively long end} extensions which con prises, charging raw" fuel into one end e: tension of said conduit, 1-l 1eating; fuel and: di tilling th e 'v olatile matter. from said-fuel I an interniediate localized carboni zing se tion'of said chamber, passing the gasesjal vapors from said carbonizing section inch itact withraw fuel occupying the said e1 extension of said conduit to condenseta forming constituents of the products of t? distillation ,of-the fuel in said carbonizii section on-Isai'd raw fuel, periodically revel ing the direction of flow. of the gas curre 'passing through the raw fuel, to carry ba theconden'sed tar, by means of the revers gas current, into contact with hot fuelfi'n t said intermediate section of said conduit a; to re-vaporize the said tar, withdrawing t reeva'p'oriz'ed tar from said conduit, wit drawinghot carbonized fuel from said i termediate'section into the other of said e: extensions of said conduit, contacting wi hot carbonized fuel in said end extensior current of cold deluminated gas, to trans: to said cold deluminated gas substantia all the sensible heat of the said carbonir fuel above the initial temperature of s: deluminated gas, and passing the heated luminated as in contact with fuel to be c bonized, w ereby the sensible heat of s: carbonized fuel is transferred to the s: fuel togbe carbonized.

5. The method of carbonizing fuel a making as in a closed conduit having co p'arative y long end extensions and an termediate localized carbonizing sect; which comprises, advancing a body of f throughe sald conduit, the said body of f being advanced through said conduit 2 maintained in said conduit by withdraw material from one end extension of said 0 duit and adding raw fue'l tothe other 4 extension of said conduit, heating said f and distilling the volatile 'matter from s fuel in said intermediate section of said c duit;'passing the products of such disti tion.in contact with the raw fuel occupy the said end extension of said conduit, condense tar-forming constituents of s distillation products on said raw fuel, riodically reversing the direction of Hon the gaseous current to carry back the s tar into the said intermediate section of s conduit in contact with hot .fuel undergo carbonization therein to re-vaporize the s tar and to convert heav hydrocarbons of the tar vapors into dilicultly condensable gases of lOW81 l'IlOlGOl1l1I weights, and withdrawing the current of gas together with the gases derived from the said tar from said conduit.

6. The method of carbonizing fuel and making gas in a closed conduit having comparatively long end extensions and an in termediate localized carbonizing section which comprises, advancing a body of fuel through said conduit, the said body of fuel being advanced thropgh said conduit and maintained in said conduit by withdrawing material from one end extension thereof and charging raw fuel into" the other end extension thereof, heating 'said fuel and dis tilling volatile matter from said fuel in said intermediate section of said conduit, pass- .ing gases and vapors formed in said intermediate section in contact with raw fuel occupying the said end extension of said conduit, to condense tar-forming constituents of the products of the distillation of said fuel [on said raw fuel, periodically reversing the direction of flow of the gas current pass ing through said raw fuel by introducing into the end extension of said conduit occupied by said raw fuel and passing through said raw fuel a stream of relatively cool gaseous fluid to cool saidraw fuel and to cairy back condensed tar by the said gaseous fluid into contact with hot fuel in the said intermediate section of said conduit to revaporize said tar and toiconvert heavy hydrocarbons of the tar vapors into simpler gases which are either permanent gases or difiicultly condensable vapors, withdrawing the gases introduced into said condult together with the tar gases and vapors formed from said chamber and transferring heat of the coke residue of s aid fuel to a portion of raw fuel.

7. The method of carbonizing fuel and making gas in a closed conduit having comparatively long end extensions and an intermed1- ate localized carbonizing section which com prises, advancing a body of fuelthrough-said conduit, the said body of fuel being advanced through said conduit and maintained in said conduit by withdrawing material from one end extension thereof and charging raw fuel into the other end extension thereof, heating said fuel and distilling volatile matter from said fuel insaid intermediate carbonizing section of said conduit, parsing gasesand vapors from said intermediate section in contact with raw fuel. occupying the said end extension of said conduit, to condense the tar-forming constituents of the products of the distillation of said fuel in said intermedinate section on saidraw fuel, periodically reversing the direction of flow of the gas current passing through said raw fuel by introducing into the end extension of said conduit occupied by said raw fuel and passing through said raw fuel a stream of mixed deluminated gas and water vapor relatively cool to carry back the condensed tar by the reversed gas current into contact with hot fuel in the said intermediate section of said chamber to revaporize said tar and to convert heavy hydrocarbons of the tar vapors into gases of lower molecular weight which are for the most part either permanent gases of diflicultly condensable vapors, withdrawing from said chamber at a locality within the carbonizing region of the same both the stream of introduced gases and the tar gases, restoring the normal direction of gas flow through said chamber, contacting with hot carbonized fuel from the carbonizing operation a current of cold deluminated gas, whereby substantially all of the sensible heat of the carbonized fuel above the initial temperature of said deluminated gas is transferred to said deluminated gas and passing the heated deluminated gas in contact withfuel to be carbonized, where by the said sensible heat of said coke is transferred to the said fuel to be carbonized. 8. The method of carbonizing fuel and making gas in a plurality of substantially vertical conduits having comparatively long end extensions and intermediate localized carbonizing sections, which comprises advancing a body of fuel through each of said conduits, the said bodies of fuel being advanced through said conduits and maintained in said conduits by charging raw fuel into the up er end of said conduitsand removing carbonized fuel from the lower end of said conduits, introducing a stream .of deluminated gas and water vapor into the lower end of each of said conduits, conducting the said gaseous stream upward through the material in said vertical conduits, withdrawing gas from the tops of said chambers, periodically reversing the direction of flow of said deluminated gas and water vapor, the said gas and water vapor during reversal being introduced at the tops of said conduits and withdrawn from localities within the intermediate carbonizing sections of said conduits.

9. The method of carbonizing fuel and making gas in a plurality of substantially vertical conduits having comparatively long and extensions and intermediate localized zarbonizing sections, which comprises advancing a body of fuel through each of raid conduits, the said bodies of fuel being advanced through said conduits and maintain ed in said conduits by charging raw fuel into-the upper said localized earbonizing sections to a carbonizing temperature, introducing into the lower extension of each of said conduits a stream of relatively cool deluminated gas and water vapor, conducting said gaseous stream up through said fuel 'into the carbonizing section of said conduit, conducting the said stre fuelupward in contact with the raw fuel in the upper extension of said charge column,

withdrawing the said gases from said retorts near the mouthpieces of the same, removing a major portion of theilluminating constituents from a portion of said gases and reintroducing the delumihated gas and water vapor into the lower end extensions of said conduits, periodically reversing the direction of flow of said deluminated gas and Water vapor, the said deluminated gas and water vapor during reversal being introduced into the upper end extensions of said conduits, conducting the deluminated gas downthrough the raw fuel in said end extensions and withdrawing the introduced gas and the gases generated in said retorts during reversal from localities within the intermediate 'carbonizing regions of said conduits.

10. The method of carbonizing fuel and making gas in a plurality of substantially vertical retorts having comparatively long extensions, which comprises maintaining a fuel body substantially filling each of said retorts, advancing said fuel body through saidflretorts by charging raw fuel onto the upper portions of said fuel bodies and Withdrawing" carbonized fuel from the lower arts of said fuel bodies, subjecting the fuel in the middle portions of the said fuel bodies to a localized carbonizing temperature, ad-

'vancing the carbonized fuelinto'the lower end extensions of said retorts, withdrawing gas from the upper end extensions of said retorts, removing illuminants from a portion of the Withdrawn gas, substantially saturating the deluminated portion of said gas with water vapor, introducing the mix-c I ture of deluminated gas and water vapor into the lower end extensions of sai retorts, passing the said gaseous mixture up through the relatively hot carbonized fuel in the said lower extensionsof said retorts,

whereby sensible heat of said coked fuel is transferred to said stream of deluminated f gas and water vapor, passing the heated deuminated gas and water vapor through the said carbonizing reglons of said retorts,

whereby illuminating constituents are again taken up by the said gaseous stream, passing the said gaseous stream and the gases evolved in the said carbonizin regions of said retorts up through the re atively cold raw fuel in the upper end extensions of said retorts, to condense thg ondensable vapors of said gases on said raw fuel, periodlcally reversing the direction of flow of said stream of deluminateehgas and water of deluminated gas and gases evolved in the carbonization of said vapor, the said stream during reversal being introduced into the said upper end extensions of said retorts and passed down through the said fuel bodies to carry down.

the condensed matter into contact with the hot carbonized fuel to re-vaporize the said condensed matter and to cool said raw fuel,

maintaining said fuel bodies in said retorts by withdrawing carbonized fuel from the lower portions of said fuel bodies and charging fresh fuel onto the upper portions of said fuel bodies, subjecting the fuel in the middle portions of said fuel bodies to a carbonizing temperature, to distil the volatilizable matter from said fuel, condensing the tar-forming constituents of the distillation gases by contacting the said gases with the raw fuel in the upper end extensions of said retorts, withdrawing the relatively tarfree gases from the upper end extensions of said retorts, and periodically carrying the condensed tar into contact with the hot fuel in the corbonizing regions of the retorts by introducing a stream of deluminated gas and water vapor near the tops of said retorts and withdrawing the gas introduced and, the evolved gases from the carhonizing regions of said retorts. I

12. In the carbonization of coalin a plurality of vertical retorts having comparatively long end extensions and intermediate localized carbonizing regions, the step which comprises periodically introducing into each .of said retorts near the top of the same a stream of deluminated gas and water vapor under pressure, and forcing said streams downward through the upper portion of the fuel bodies in the retorts into the carbonizing regions of said retorts, whereby inter; in the interior of said stices are opened up charge columns WhICl'l permit the free passage of, the gases through said charge columns" during the normal operation ofd said retorts.

13. In the carbonization of coal in a plurality of vertical retortshaving a locallzed carbonizing region, the step which comprises periodicall interrupting thenormal discharge of gas rom said retorts, introducing streams of deluminated gas under pressure into said retortsnnear {the tops of the same, forcing said streams downward through the upper portions of the fuel bodies in said retorts: into :the carbonizing '"r ginzns 0% said retorts, to open up interstices Signed at New York city inthe county of N ew York and State of New York 28th m. the interiors of said fuel bodies to pervzmifi; of the free passage of the gases through day of January A. D. 1915. amid fuel bodies during the normal operation HENRY L. DOHERTY. of said retorts, and exhausting the intro- Witnesses:

dmcsrfgilses and'the evolved gases from the Tnos I. CARTER,

WILLIAM G. PREGAL.

said. carbonizing' regions of the said retorts.

Commissinner of Patents,

Furnish of this patent may be obtained for five cents ach, by addressing the washing :1. c." 1 P v 

